Kazuo Isaka

Laser recording and image-quality evaluation

Various kinds of printers electrophotographic printers ink jet printers thermal printers etc. have been commercialized especially for DTP. The authors however have been unsatisfied with the image-quality of these printers. A laser recording apparatus was made for our study which is composed of a laser diode a polygonal mirror and a F-theta optical system. The recording apparatus selectively provides high density pixel (600 900 or 1 200 dpi). The gradation of each pixel is obtained by modulating the pulse width of the laser diode oscillation. We used the silver halide paper (PD-100WP Fuji Photo Film Co. Ltd. ) with the good spectrum sensitivity for the laser diode of 780 nm wavelength. The recorded image samples with three kinds of pixel densities and with gradation levels ranging from 16 to 166 were used for being evaluated by sixteen persons. As a result of analysis on the evaluated data we found out some relations between pixel densities and gradation levels for the satisfactory image-quality. 2.